AnsweredAssumed Answered

ADE7878 Calibrating IRMS and IGAIN

Question asked by MrQ on Nov 25, 2016
Latest reply on Dec 2, 2016 by dlath

Hi,

I'm using the ADE7878 for power monitoring and I have problems calibrating the IRMS.

I use current transformer with a CT of 2000. So I get the following value for IFS:

IFS = (0.5*2000) / (7,07 *SQR(2)) = 100.0151

My nominal current is  2.08A.

So I get an IrmsREF of 87179.

Without AIGAIN, the AIRMS register has the following value: 91500 (0.0915A).

I calculate AIGAIN: IrmsREF/IRMS -1 = (87179/2080000)-1)= -0.95808=0x855D67 and write 00855D67 to the AGAIN register.

Now with AGAIN the AIRMS register has the following value: 187259 (0.187259 A).

Where is the mistake?

 

Best regards Jens

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